eNature www.enature.com Bird lovers should flock to this site, which includes tips on equipment, opportunities to pose questions to an online naturalist, and a clever search program that helps stumped birdwatchers identify unfamiliar birds. You can even create online "life" of birds and other wildlife that you have seen over the years.   The Living Edens www.pbs.org/edens Based on a PBS series of the same name, The Living Edens transports you to undisturbed corners of the world. From the Ngorongoro crater in Africa to Canyonlands National Park in Utah, each of more than 15 locations comes to life via geological information and wildlife profiles.   Earthquake Information from the USGS quake.wr.usgs.gov Produced by the U.S. Geological Survey, this handy reference site presents current earthquake conditions throughout the United States and the world in a simple format. Clickable maps, updated hourly, show the location and strength of the week's quakes. And resource pages define terms, relay the history and science of earthquakes, help you prepare for an earthquake, and tell you what to do if you get caught in one.   6 Billion Human Beings www.popexpo.net If you're 38 years old, there are now about twice as many people on Earth as when you were born, and about 30 percent of the people born that year are already dead. You can learn facts like these by plugging your age into one of the many interactive "Did you know?" games at this online exhibit from Musée de l'Homme in Paris, part of France's National Museum of Natural History. The exhibit is designed to help visitors "understand why the world's population has exploded in recent years and why it might stabilize during the next century."   Environment News Service www.ens-news.com Independently owned and operated, the ENS provides timely reports from around the world on a wide range of environmental topics, without the usual spin provided by an affiliated business or environmental group. The wire service covers legislative and judicial decisions, demonstrations, conferences, and other daily news that affects land use, public health, and wildlife. Also find links to information about becoming an Earth-smart consumer, planning eco-travel, learning about local environmental problems, and making businesses more sustainable.